What should we do if the touch screen voltage is abnormal?

In daily use, PCAP touch screens occasionally experience malfunctions due to voltage issues. As a touchscreen manufacturer, we have compiled the three most common voltage related issues and their solutions, hoping to help you quickly troubleshoot them.
 

The first scenario: completely unresponsive to touch
This is often caused by insufficient power supply or reversed polarity. Firstly, check if the connector is securely plugged in, and then use a multimeter to measure if the voltage between VCC and GND is within the specified range. We have encountered a situation where a customer connected a 5V PCAP touch screen to a 3.3V power supply, causing the driver IC to malfunction. If the voltage is normal but there is still no response, it may be due to a blown fuse inside the screen, and the manufacturer needs to be contacted for repair.
 

Second scenario: Touch point drift
When there is a large ripple in the power supply, there will be a regular shift in touch coordinates. This situation is more common in devices powered by switch mode power supplies. There are three solutions: 1) Install an LC filter circuit at the touch screen power input terminal; 2) Switching to a linear regulated power supply; 3) Ensure that the PCAP touch screen is well grounded. Our test data shows that good filtering can reduce coordinate drift by over 80%.
 

The third scenario: intermittent failure
This is usually a manifestation of poor contact or voltage fluctuations. Suggest checking if the gold fingers of the FPC connector are oxidized and monitoring if the operating voltage is stable. For industrial applications, we recommend using a touch screen with voltage monitoring function. When the voltage is abnormal, an alarm will be issued through LED indicator lights or communication interfaces.
 

Prevention is better than cure. We suggest that customers fully consider power supply design during the new product development stage: reserve 10% -20% voltage margin; Avoid voltage drop caused by long-distance wiring; Power the PCAP touch screens separately rather than sharing power with other modules. Our technical team can provide professional PCB layout and power design recommendations.
 

Remember, the safest approach when encountering any voltage related issues is to promptly shut down the power and contact a professional. Forcefully increasing the voltage or modifying the circuit may cause permanent damage. We provide detailed technical documentation and after-sales support for all products to ensure that you can use them with confidence.